CONTINUOUS CUTTING AND RAPID DEVELOPMENT
The need for speed…and safety
With orebodies going deeper and ventilation
requirements increasing, miners are seriously considering
the use of continuous cutting and rapid development
technologies to fight this rising cost and safety tide. Dan
Gleeson looks at the latest innovations in the sector
he underground continuous cutting/rapid
development space has become a lot more
competitive in recent years, with the
advent of several new machines aimed at
providing the productivity and safety boosts
conventional drill and blast techniques cannot.
The hard-rock industry is still some way
behind its soft-rock counterpart when it comes
to adopting these innovations, with very few
commercial references available, but there are
trials taking place that are being eagerly
watched by the wider industry.
As Anglo American – one forward-thinking
mining company – says, “It took the coal
industry two decades to move from
conventional mining to mechanisation and
partial automation, so the learnings from these
underground cutting and rapid mine
development projects, applicable to
underground diamond, as well as platinum
mining, are exciting for Anglo American.
“They are also vital to the future of
underground mining in an era of deeper mines,
increasing costs and falling productivity.”
T
Testing it out
In terms of where the new equipment is being
tested, it is good to start off with Anglo
American and its underground platinum
operations in South Africa.
“We are using automation and continuous
rock cutting vehicles to safely extract the
targeted ore deep underground without the
need for explosive blasting, thereby creating far
greater rock stability and less variance in the
40 International Mining | DECEMBER 2018
quality of the ore we extract,” the company
explained in a blog earlier this year.
Anglo has some form when it comes to
applying new technology, having previously
used tunnel boring machines (TBM) for mine
infrastructure, and carrying out remote and
partly-automated operation of longwalls at its
Australia coal operations.
The miner wants to use hard-rock
mechanised cutting as it provides the ability to
mine lower-grade ores and complex mineralogy,
creating a safer environment and lower
operating costs “while enhancing the value of
the mineral resource in the ground”, it says.
The Rapid Mine Development System
(RMDS), developed in tandem with OEM Epiroc
(and which Epiroc refers to as the Mobile Miner
22H), is currently being trialled at the
Twickenham platinum mine in the renowned
Bushveld Igneous Complex.
“The RMDS excavates a rectangular-shaped
tunnel, important for roof stability purposes in
platinum mines, as well as providing the flat
floor needed by mine vehicles,” Anglo said.
The RMDS/Mobile Miner 22H (H for
horizontal) is the smallest machine in Epiroc’s
Mobile Miner family and, unlike some other
technologies in this growing space, features
TBM-type cutting technology.
The Mobile Miner family consists of powerful
mechanical rock excavation machines that can
be fully customised. They use a well-known
steel disc cutter technique, packaged in a small
and flexible machine that Epiroc says is ideal for
mining use.
Epiroc’s Mobile Miner 40V is typically used in
narrow vein mining
As well as removing people from dangerous
areas underground, the system causes less
damage to the overhead walls, reducing the risk
of collapse, and enables greater ore excavation
progress as there is no time lost for explosives
blasting, according to Anglo.
The RMDS, or Mobile Miner 22H, trial started
at the Twickenham mine, currently on care and
maintenance, around 18 months ago and is due
to finish by the end of the year.
The machine is typically used in low seam or
low-profile mining when a tunnel as low as 2.2 m
is needed. It is typically capable of 10-12 m/day
advances depending on rock type.
Johnny Lyly, head of Epiroc’s hard-rock cutting
division, told IM the machine had met the
majority of targets set by Anglo American at
Twickenham.
This machine, in the case of the Twickenham
trials, is backed up by a continuous haulage
system provided by Sandvik, which connects the
RMDS to the mine’s fixed conveyors, according
to Anglo. It can be operated remotely, which is
another potential safety benefit.
Sandvik’s MN220 Reef Miner has also been
undergoing trials with the mining company in
South Africa.
The MN220 “incorporates cutting and roof
bolting and is designed for mining narrow
mineral reefs in hard rock”, Anglo said. It is up
to three to four times faster than conventional
drill and blast methods, according to the miner.
The undercutting technology carries out
extraction in one metre reefs to ensure delivery
of high-grade ore with precision mining.
After successful proof of concept trials at the
company’s Bathopele platinum mine in South
Africa, in 2013, it is now being “optimised”